Adjustable cool-down control for dryer cycle



Dec. 27, 1966 w. GRAHAM 3,293,769

ADJUSTABLE COOL'DOWN CONTROL FOR DRYER CYCLE Filed June 18, 1964 lNVENTOR.

Dcgle W Graham A TTOR E YS Uited States Patent OfiFice 3,293,769Patented Dec. 27, 1866 3,293,769 ADJUSTABLE CGGLDGWN CGNTRGL FGR DRYERKIYCLE Dale W. Graham, Benton. Harbor, Mich, assigncr to This inventionrelates to improvements in clothes dryers and more particularly relatesto a control system for a clothes dryer wherein a cool down periodcompatible with the size and type of load being dried may bepreselected.

The invention specifically relates to a clothes dryer and sequentialcontrolling mechanism therefor, in which the programming of one or moreof the sequential operations of a fabric treatment cycle, such as thecooldown period or heat-01f period, may be adjusted or modified withrespect to the duration of another operation of the treatment cycle orheat-on period.

The control mechanism includes a timer mechanism incorporating a motordriven shaft having at least one cam thereon regulating the heating ofthe air stream supplied to the dryer drum and the termination of thefabric treatment cycle and having modifying cam means associatedtherewith which may be so arranged as to vary the length of an operationin the cycle of fabric treatment by manual positioning of the modifyingcam.

In the disclosed embodiment of the invention, the modifying cam isadapted to provide a cool-down time of a clothes drying apparatus inwhich the heat is turned off and the blower and tumbling drum continueto operate, although it should be understood that the principles of thepresent invention may also be applied toward modifying the heat-on timeas well as the cool-down time.

A principal object of the present invention is to provide a clothesdryer and control therefor operable to selectively provide an operationin the fabric treatment cycle of a clothes dryer in addition to theheating operation, the length of time of which may readily be varied.

Another object of the invention is to provide an improved form ofcontrol means for controlling the cycle of operation of a clothes dryerin which a cool-down time of the treatment cycle may be provided andselected in accordance with the size of load and material to be dried.

Another object of the invention is to provide a sequential controllerparticularly adapted to control the treatment cycle of a domesticclothes dryer including a cam driven by a timer motor and positionableto control the heat-on time of drying and .a second cam rotatabletherewith and adjustable relative thereto to modify the contour of thecontrol cam and thereby provide cooldown time of the clothes dryer whichmay readily be adjusted.

These and other objects of the invention will appear from time to timeas the following specification proceeds and with reference to theaccompanying drawing wherein:

FIGURE 1 is a diagrammatic view of a domestic clothes dryer looking atthe dryer from the back thereof with certain parts of the back coverbroken away;

FIGURE 2 is a top plan view of the timer shaft and cams of a timer fordomestic clothes dryer showing the control cams in horizontal section;

FIGURE 3 is an end view of the dial knob shown in FIGURE 2 and showingthe control means for varying the cool-down time of the dryer; and

FIGURE 4 is a diagrammatic view illustrating the timer and modifyingcams and the control circuit to the heater and dryer drum motor.

In the embodiment of the invention illustrated in the drawings, I haveshown in FIGURE 1, in general diagrammatic form, a clothes dryer 10having a control therefor of a type suitable for carrying out myinvention. The clothes dryer 10 generally includes a tumbler drum 11rotatably journalled in a cabinet 12 for the clothes dryer. The tumblerdrum 11 is driven from a motor 15, to tumble clothe-s therein, through aconventional form of belt drive 16. A heater duct 17 extends verticallyalong a back plate 19, extending along the back of the dryer drum 11 andcommunicating with air at atmospheric pressure at the front of thecabinet 12 through a duct 29. The heater duct 17 has communication withthe dryer drum through a port 21.

A suitable heater 23 (FIGURE 4), diagrammatically shown as being anelectric heater, is mounted within the heater duct 17 to heat the airdischarged into the dryer drum and thereby effect the drying of clothesin the drum. While the heater 23 is shown as being an electric heater,it need not be an electric heater, but may be a gas heater controlled byelectrically energizable gas valves. Air is drawn into the duct 20, theheater duct 17, through the dryer drum by a blower 24 driven from themotor 15 through a belt drive 25 and having communication with the backof the dryer drum through the plate 19. Spent air drawn through thedryer drum by the blower 24, and tumbling clothes therein, is dischargedto the atmosphere through a port opening 26.

A sequential controller or timer generally indicated by referencecharacter 27 is provided at the back of the cabinet 12 and includes adial knob 29, pinned or otherwise secured to a timer shaft 30, suit-ablyjournalled in a casing 31 for the timer and driven from a timer motor 32in a suitable manner. The timer motor may be a conventional form ofelectrically enengizable timer motor having reduction gearing in thehousing for the timer motor for driving the timer shaft 30 forsubstantially one complete revolution, in the time required to dry anormal heavy load of goods in the tumbling drum 11. The timer motor andthe drive to the timer shaft 13, therefore, need not herein be shown ordescribed further.

A cycle control or timer cam 33 is pinned or otherwise secured to thetimer shaft 30 for rotation therewith. Said cycle control or timer cam33 has a raised peripheral cam surface 35 which extends for a greaterportion of the circumference of the cam and a low portion 38 of the camwhich connects opposite ends of the high portion 35 together. The highportion 35 determines the heating period of the heater 23, which may bea resistor type of electrically energizable heater, while the lowportion 38 determines a plurality of off positions.

As shown in FIGURE 4, a resilient switch arm 37 has a cam follower 36and a contact 42 on the end thereof engage-able with a contact 43 on aresilient switch arm 44. Engagement of the contact 42 with the contact43 will complete an energizing circuit to the timing motor 32 and thedrive motor 15. The switch arm 44 also has a contact 45 on the oppositeside thereof from the contact 43 for engaging a contact 46 on aresilient switch arm 47. Engagement of the contact 45 with the contact4-6, effected by the riding of the follower 36 on the raised cam surface35, will complete an energizing circuit to the heater 23, to supply theheat in the heater duct 17 necessary to dry articles of clothing and thelike in the tumbling drum 11, in a predetermined period of time,depending upon the type and weight of the articles to be dried.

A cycle modifying cam 50 is rotatably mounted on the shaft 30 adjacentthe cam 33 and has a plane face 54 3 frictionally engaged with a planeface 34 of the cam 33, biased by a spring 51 encircling the shaft 31 Asdiagrammatically shown in FIGURE 2, the spring 51 is interposed betweena collar 52, pinned or otherwise secured to the shaft 39, and a hub 53extending from the cycle modifying cam 50. The cycle modifying cam,therefore, normally rotates with the cam 33, but may be moved withrespect to the cam 33, when it is desired to change or modify thecontour of the cam 33 to give a predetermined effective profile of thecombined cams.

As diagrammatically shown in FIGURES 2 and 3, an arm 55 extends radiallyoutwardly of the hu 53 and is suitably secured thereto. An arm portion56 extends axially of the outer end portion of the arm 55 over the dialknob 29 on the shaft 36. The arm 56 has an inwardly extending indexingend or pointer 59 terminating in a point and cooperating with indicia 66to an outer inclined face 61 of the dial knob 29. The indicia 6d are inregistry with the low portion 38 of the cam 33 and correspond to thetime of a cool-down period attained by movement of a raised cam face 62of the cam 50 to mask said low portion 38. As for example, when thepointer 59 is in registry with the numeral 12, the dryer drum willrotate for a cool-down period of 12 minutes with the heat off.

The cycle modifying cam 50, as shown in FIGURE 4, ha a raised cam face62, extending for a portion of the circumference thereof and terminatinginto a reduced diameter face 63 of the same diameter as the reduceddiameter face 38 of the cycle control cam 33.

The rise of the cam face 62, when engaged by the follower 36, issufiicient to engage the contact 42 with the contact 43 and maintain acircuit to the motor 15 and the timer 32. When the follower 36 ridesalong a reduced diameter face 63 of the cam 50, and along the face 38 ofthe cycle control cam 33, the contact 42 will be moved out of engagementwith the contact 43 and the drive motor 15 and timer motor 32 will bedeenergized and the dryer will stop. Thus cam faces 38 and 63 provide aplurality of off positions, determined by selection of the duration ofthe cool-down period.

It will be noted from FIGURES 2 and 3 that the cycle modifying cam 50 ispositioned by operation of the arm 55. By moving said arm in acounterclockwise direction, the cool-down period is increased. The cams33 and 50 are rotated together in a clockwise direction by the timer tocarry out a sequential treatment cycle.

It may further be seen from FIGURES 3 and 4 that the cycle modifying camcan be adjusted to vary the cool-down period from zero to 12 minutes andthat when positioning the cycle modifying cam to select the cooldownperiod, the cam 33 may be held from rotation by holding the dial knob29, while the cam 50 is rotated by grasping the pointer 59 and movingsaid pointer in registry with a desired cool-down period indicated onthe dial knob 29, it being understood that the dial knob 29 is turned ina clockwise direction to select the length of a drying cycle inaccordance with the type of goods to be dried.

The cycle modifying cam shown in the drawings is of a configurationwhich varies the cool-down period, leaving the heat-on period constant,and thus varies the total cycle time within the limits of the cool downperiod. The cycle modifying cam, however, may be of a configurationwhich varies the heat-on period, leaving the total cycle time constant.In the latter case, the cycle control cam may be provided with thecombined cam contour shown in FIGURE 4 and the cycle modifying camprovided with a peripheral raised portion equal to the diameter ofraised portion 35 shown in FIGURES 2 and 4. The cycle modifying cam maythen be positioned in such a manner as to increase the heat-on portionof the treatment cycle while simultaneously decreasing the cool downportion of the cycle.

While I have herein shown and described exemplary forms in which theinvention may be embodied, it may readily be understood that variousvariations and modifications in the invention may be attained withoutdeparting from the spirit and scope of the novel concepts thereof.

The embodiments of the invention in which an eX- clusive property orprivilege is claimed are defined as follows:

1.. In a control for a clothes dryer having a drying chamber,

motor-driven means for tumbling clothes in the drying chamber and fortranslating air thereover and a heater for heating the air,

the combination of a rotatable sequence timer manually movable from aninactive position to selective active positions and controllingoperation of the heater and the motor driven means,

a multiple parts cam rotatable with said timer,

and said multiple parts together with one another forming a single camprofile having a peripheral cam high portion, a peripheral cam raisedportion, and a peripheral cam low portion,

and multiple switch means actuatingly operated by said cam profile andengaging a corresponding multiple of cam followers disposed in operativeregister with high portion, said raised portion, and said low portion toope-rate the dryer automatically under the control of said rotatablesequence timer through a drying cycle including (1) a heat-on period,and (2) a cool-down period and an (3) off position,

said heat-on period and said cool-down period corresponding to said highand raised portions on said cam profile,

and adjustment means to selectively modify the heaton period and thecool-down period by selectively adjusting said multiple parts of saidcam to modify the profile of the cam by changing the effectivecircumferential lenth of said com high portion and said cam raisedportion.

2. In a clothes dryer having a tumbling drum, a main motor for rotatablydriving said drum to tumble goods therein for drying, a heater, andmeans for drawing heated air through said tumbling drum, the improvementcomprising:

a timer controlling the sequential operation of said dryer through afabric treatment cycle and including a timer motor for driving saidtimer,

circuit means including an energizing circuit for said main motor,

said timer motor and said heater,

a timer cam rotatably driven by said timer motor and switch meansoperated by said timer cam for controlling said circuit means,

said timer oam having a high operating said switch means to energizesaid main motor, said heater and said timer motor,

and having a low portion accommodating the opening of said switch meansand the deenergization of said main motor,

said timer motor and said heater,

and second cam means having clutching engagement with said timer cam anddriven thereby and having a cam surface adjustably modifying the lowportion of said timer cam to deenergize said heater and maintain saidmain motor and said timer motor in operation to provide a cool-downportion of said fabric treatment cycle,

said switch means including at least three switch arms,

a follower on one switch arm engaging said timer cam and operatedthereby to complete said energizing circuit through said three switcharms during rotation of said timer cam as said follower rides on thehigh portion thereof and operable to break said energizing circuitbetween said switch arms as said follower rides on the low portion ofsaid timer cam,

and wherein said second cam has a rise spaced radially inwardly of thehigh cam surface of said timer cam and radially outwardly of the low camsurface of said timer cam and engaged by said follower to maintain saidenergizing circuit between two of said switch arms and to deenergize thethird of said switch arms, to eifect deene-rgization of said heater andthe continued operation of said main motor and said timer motor for acool-down portion of said fabric treatment cycle,

and manually operable means for selectively adjusting the position ofsaid second ca m with respect to said timer cam and the duration of saidcool-down portion.

3. In a dryer as defined in claim 2 and further characterized by saidsecond cam being rotatably adjustable with respect to the cam in adirection opposite to the direction of rotation of said cam to controlthe sequential operation of the dryer,

References Cited by the Examiner UNITED STATES PATENTS Kriechbavm 34-45X Kostelich 3445 Uilman 74568 Cook 20038 X Hendry 200-38 X Genbavffe3445 X 20 FREDERICK L. MATTESON, JR., Primary Examiner.

D. A. TAMBURRO, Assislant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3, 293,769 December 27, 1966 Dale W. Graham It is hereby certified that errorappears in the above numbered patent requiring correction and that thesaid Letters Patent should read as corrected below.

Column 4, line 26, before "high" insert said line 40, for "lenth" readlength same line 40, for "com" read cam line 56, after "high" insertportion Signed and sealed this 24th day of October 1967,

(SEAL) Attest:

Edward M. Fletcher, Jr. EDWARD J. BRENNER Attesting Officer Commissionerof Patents

1. IN A CONTROL FOR A CLOTHES DRYER HAVING A DRYING CHAMBER,MOTOR-DRIVEN MEANS FOR TUMBLING CLOTHES IN THE DRYING CHAMBER AND FORTRANSLATING AIR THEREOVER AND A HEATER FOR HEATING THE AIR, THECOMBINATION OF A ROTATABLE SEQUENCE TIMER MANUALLY MOVABLE FROM ANINACTIVE POSITION TO SELECTIVE ACTIVE POSITIONS AND CONTROLLINGOPERATION OF THE HEATER AND THE MOTOR DRIVEN MEANS, A MULTIPLE PARTS CAMROTATABLE WITH SAID TIMER, AND SAID MULTIPLE PARTS TOGETHER WITH ONEANOTHER FORMING A SINGLE CAM PROFILE HAVING A PERIPHERAL CAM HIGHPORTION, A PERIPHERAL RAISED PORTION, AND A PERIPHERAL CAM LOW PORTION,AND MULTIPLE SWITCH MEANS ACTUATINGLY OPERATED BY SAID CAM PROFILE ANDENGAGING A CORRESPONDING MULTIPLE OF CAM FOLLOWERS DISPOSED IN OPERATIVEREGISTER WITH HIGH PORTION, SAID RAISED PORTION, AND SAID LOW PORTION TOOPERATE THE DRYER AUTOMATICALLY UNDER THE CONTROL OF SAID ROTATABLESEQUENCE TIMER THROUGH A DRYING CYCLE INCLUDING (1) A HEAT-ON PERIOD,AND (2) A COOL-DOWN PERIOD AND AN (3) OFF POSITION, SAID HEAT-ON PERIODAND SAID COOL-DOWN PERIOD CORRESPONDING TO SAID HIGH AND RAISED PORTIONSON SAID CAM PROFILE, AND ADJUSTMENT MEANS TO SELECTIVELY MODIFY THEHEATON PERIOD AND THE COOL-DOWN PERIOD BY SELECTIVELY ADJUSTING SAIDMULITPLE PARTS OF SAID CAM TO MODIFY THE PROFILE OF THE CAM BY CHANGINGTHE EFFECTIVE CIRCUMFERENTIAL LENTH OF SAID COM HIGH PORTION AND SAIDCAM RAISED PORTION.